Fluid-pressure control.



P. E. MARTIN. l FLUID PRESSURE CONTROL.

APPLICATION FILED 00113, 1911.

Patented June 18, 1912.

/ 1 mllf fllll.

AHNI IEBJEIDEIBJICK E. MARTIN, OF BONAMI, LOUISIANA.

FLUID-PRESSURE contraen Patented une 18, 1912.

To all whom it may concer-n Be it known that I, FREDERICK E. MARTIN, a citizen of the United States, residing at Bonami, in the parish of Calcasieu and State of vLouisiana, have invented certain new and useful Improvements in Fluid-Pressure Control; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

rl`his invention relates to a fluid pressure control and especially to improvements in the device disclosed by my former applica tion filed March 22, 1911, Serial No. 616,286.

The main objectofthe present invention' is to arrange the ports and passages in the piston and also the valve for controlling same'.

A further object of my invention is to provide an improved duid-actuated control'device ladapted for eticient operation, and which can be manually actuated by the operato-r upon failure of the actuating fluid.

The invention'will be understood from the following description taken in connection with the accompanying drawing, illus trat-ing the preferred embodiment thereof, and the novel features of the invention will be distinctly pointed `out in the appended claims.

In the drawing like characters of reference indicate corresponding parts.

Figure 1 is a longitudinal sectional view of a fluid pressure control constructed in accordance with my invention; Fig. 2 is a transverse section taken on line 2 2, Fig. 1, the exhaust pipe being omitted; and, Fig. 3 is a similary view taken on line 3 8, Fig. l.

1 represents a cylinder provided with ends 2 having feet' which are secured to a suitable support 4 by bolts 5. A pressure supply pipe 6, provided with a valver'fl, terminates in branch pipes 8 and 9, which enter the cylinder near its ends, as at 10, for conveying steam or fluidpressure thereto.

A piston 11,'provided wit-h the usual packing rings 12 near its ends, is slidably mounted in the cylinder, and has a reduced central diameter to provide an exhaust chamber, 13 of such a length as to always be in communication with an exhaust pipe '14 connected to the cylinder centrally of its ends. The

piston is centrally bored at 15 for receiving a slidably mounted valve 16, which has a reduced central portion 17 leaving a space a valve or other means which it is desired to control or shift. A tube 28 projects from the other end of the piston through the end of the cylinder, which is also provided with a stuffing box, as shown at 24. Slidably mounted in the tube 23 isa valve stem 25, which is connected with thevalve 16; said valve stem being adapted to be manually op,- erated'in any Well known manner, as by a lever. A stuffing box 26 is provided at the projecting end of the tube 23.

A plurality of exhaust ports 27 and 28 extend inwardly on an inclination from each end of the piston 11, and are adapted to communicate alternately with the space 18 of the valve 16 as same is reciprocated, by the operator, to permit the escape of the fluid from the corresponding ends of the cylinder. Passages 29 and 30 connect each end of the bore 15 .with the exhaust chamber 13, and the passages at one end of lt-hebo're are closed :by the valve 16 when said ports at the corresponding ends of the cylinder are 'in communication with the exhaust space 18 of the valve. The passages 29and'30 thus obviate all danger of pressure accumulating in either end of the bore 15 by steam leakage past the valve 16, thereby/insuring aperfect balance of said valve at all times.

The operation is as follows z-Assuming the parts are in the relative positions shown in Fig. 1 of the drawings, and steam or other fluid pressure is admitted into the oppositie ends of the cylinder through the ranch pipes 8 and 9, the pressure is equalized on the opposite ends of the cylinder and upon'the opposite ends of the piston 11, and

consequently the piston is balanced and will not move longitudinally in the cylinder. Assuming it is desired to have the piston 11 and the rod 21, to which it is attached, move toward the right an operator moves the stem 25 and the valve 16 toward the right whereby the exhaust ports 28 are uncovered by the valve, andthe Huid pressure from the right end of the cylinder is allowed to escape through the exhaust space 18 of the valve,

through the recess 19 and apertures 20 of the piston to the exhaust chamber 13, and then through the exhaust pipe 14. As the pressure is reduced at the right end of the piston, the excessive pressure at the other end forces the piston to the right until the ports 28 are again closed by the valve, whenl the piston will be brought to rest by the equalized pressure inthe two ends of the cylinder. ,It is obvious that a reverse movement of the valve stem would reverse the operations described, and the piston Wouldbe moved toward the left. Should the actuating steamy-.supply fail, the operator can manually operate `the piston 11 by shifting the valve 16 yin the dcsireddirection until it comes in contact With;v

the adjacent closed end of the bore 15 and carries .the pisto-n alongy with it. This is a very advantageous and important feature under certain conditions, as in the application of my device for controlling the feed in saw mills, etc. 4.

It is'to be understood that slight changes inthe details of construction and combination and arrangement of the parts may be resorted to Withoutsacricing any of the advantages or departing from the spirit of the invention. i

Having fully described my invention what -I claim is 1. In a control device, the combination of a cylinder, an admission pipe communiating with the ends'only ofsaid cylinder, an

' exhaust pipe leading from Athe medial portion of'saidcylinder, a piston in said cylinder vprovidedvvith a central bore having closed ends and with ports communicatingwith the cylinder ends and said exhaust pipe, respectively, a `valve slidably mounted 1n said 4G bore, and means for shifting said valve for controlling said ports and for actuatingly I engagingsaid closed ends of the bore.

2. In a control device, the combination 'of a cylinder, an admission pipe communicating with the ends onlyv of said cylinder, `an exhaust pipe leading from the medial portion of' said cylinder, a piston insaid cylinder provided with a central borer having closed lends and ports spaced from said closed ends andcommunicating with the cylinder ends and said exhaust pipe, respectively, said piston being provided with ports leading from the end 'portions of said bore to the exhaust pipe, a valve slidably mounted in 4said bore, and means for shift-ing said valve for controlling said ports and for actuatingly engaging said closed 44endsof the bore.

3. In a control device, the combination of a cylinder, admission and exhaust pipes communicating respectively with the end and medialportions of said cylinder, a piston Within said cylinder provided with a circumferential recess communicating with said exhaust pipe,and with, a central bore having closed ends and With its medial and Vend portions communicating With such recess, sald plston being also' providedvwith,r

ports extending from the respective heads into communication lWith such central bore,

'a` valve slidably mounted in such bore for controlling the ports, and means for .shifting said valve. A

In testlmony whereof, I affix' my signature, 1n presence ofvtwowltne'sses.

FREDERICK E. MARTIN. l

Witnesses T.- M TRASHER,

J. M. WARREN.' 

